Electric paint remover



Dec. 25, 1951 L. M. CARPENTER ELECTRIC PAINT REMOVER FiledV July 24,1948 2 SHEETS-SHEET 1 L. M. CARPENTER ELECTRIC PAINT REMOVEIR Dec. 25,1951 2 SI'EETS-SI'IEET 2 Filed July 24, 1948 INVENTOR f/7\B Louis M.CARPENTER BY Y ORNEYS Aefficiently or at a rapid rate.

Patented Dec. 25, 1951 UNITED vSTATES PATENT OFFICE ELECTRIC PAIN'I`REMOVER Louis M. Carpenter, Syracuse, N. Y.

Application July 24, 1948, Serial No. 40,601

4 Claims.

. The invention relates to electric paint removers for use in burningolf paint from a painted surface.

In the past it was considered that the best method of removing old paintfrom a painted surface was to burn the paint from the surface byemploying a gasoline blow torch. Although such a blow torch waseffective for this purpose there were several serious objections to itsuse. It was heavy and awkward to use and it required a considerabledegree of skill on the part of the operator thereof to properly projectthe flame of the torch along the painted surface at the right speed soas to effect an efficient melting of the paint and at the same time tofollow the torch with a scraper blade at a correct distance therefrom tostrip the melted paint from said surface. Also, with a blow torch, evenin the hands of an experienced operator, there was always a constantdanger that the flame of the torch would enter into cracks in thewoodwork or other surfaces being operated upon and thus a fire would bestarted within the walls of the painted structure, which would possiblynot be detected until sometime after the torch had been used.

To overcome the deficiencies and hazards present when a blow torch isused for removing paint from coated surfaces, there have been-de-Veloped in recent years different types of electric paint burner deviceswhich have been designed and intended to provide a burning heat todissolve or disintegrate the paint film from a painted surface. Althoughsome of these electric paint removers have been capable of generating asuiiicient amount of heat to effectively remove the paint iilm, theyhave been found to be impractical in use for several reasons. In many ofthese paint removers, the heating elements used therein do not correctlyconcentrate or distribute the heat over the painted surface beingtreated so that a stripping of the paint can be accomplished In others,because of their construction, the heating elements used do not stand upand have a short life, thus making frequent replacement of the heatingelements necessary. In addition to these defects, in other lof theseelectric burner devices, the construction thereof has been such that theheat generated by .the heating elements tends to heat up the entiredevice to such an extent that the operating handle thereof becomes sohot that it is necessary for the user to wear heavy gloves to protectthe hands. Furthermore, in some of these prior electric paint uremoverconstructions, which may be termed open element burners (because theheating elements thereof are mounted in an exposed condition) theheating elements are positioned so far away from the painted surfacethat the heat transfer therefrom is not sumcient to properly effect adisintegration of the paint regardless of the amount of heat generatedby the said heating elements. In other devices of the open element type,where the heating elements are positioned close enough to the paintedsurface, the burner has proven to be impractical in use because thepaint melted by the heat from the heating elements tends to get into theheater coils and thuscause said coils to be short circuited and theburner rendered unusable, Finally, the use of these open element typesof electric paint removers presents a personal hazard because of thepossible chance that the users hands, or his clothes, may accidentlycome into contact with the exposed heating elements.

In other types of electric paint removers heretofcre used the heatingelements thereof have been imbedded in a block of refractory material inorder to protect the same from injury. In these constructions theconduction of the heat supplied by the heating elements to thesurrounding mass of refractory material, greatly decreased the eiiciencyof the heat radiation of the paint remover. In other words, the heatthat is supplied by the heating elements is conducted away therefrominto the surrounding mass of refractory material `rather than convertingitself into radiant energy which can be directed towards the paintedsurface to be operated upon.

It has also been found that one important feature with respect to theefciency in use of an electric paint remover, is that the heatingelements thereof should produce a high concentration of heat along theoutside edges of the device. If such concentration of the heat is notproduced at such points the paint will only become properly melted inthe central area of heating and will become cooled olf so rapidly alongthe edges of the device that the paint cannot be properly stripped off,and 4it will gum up on the edges of the scraper blade which iscustomarily used in conjunction with the paint remover. To overcome thisdiiculty of not having a proper concentration of the heat along theoutside edges of the paint remover, devices have been developed whichhave been provided with a housing over the heating elements which ismade of aluminum, and which aluminum housing is possessed with a shinyheat reflecting surface on the interior thereof which functions toreflect the heat rays, radiating from the heating element, downwardlyand toward the outside edges of the device. In these constructions,however, the shiny surface of the aluminum metal of the housing does notstand up under the intense heat conditions produced by the heatingelements and the said surface becomes smoked up and dulled, and then thepaint being removed from the painted surface gets into the reflectinghousing. This smoking and dulling of the shiny surfaces of the housingis also undesirable because then the effect of the focus of the indirectradiant rays of heat is lost, thus upsetting the proper distributionthereof along the outer edges of the device. Furthermore, as soon as theshiny surfaces of the aluminum housing disappear the radiant heat willno longer be reflected, but rather will be absorbed by the darkenedsurfaces of the housing and the constant absorption of the heat willbuild up the temperature of the aluminum metal to a point whereby itwill be radiated upwardly and be conducted to the operating handle ofthe device, and thus make said handle so hot that it will beuncomfortable to grasp.

A further deciency in the construction of some of the prior electricpaint burners has been that the heating elements used therein have beencomprised of a grid formed of short lengths of resistance Wire whichhave been fastened together in series, and high heat intensity has beenprovided by using different sized resistance wire on the outside edgesof the grid. While this arrangement of the resistance wires serves toproduce a proper distribution of the heat, it necessitates the use of amultiplicity of short coils of resistance wire which are fastenedtogether with i.

each fastening point contributing a potential weak point in theconstruction under severe heat conditions.

It is the main object of the present invention to provide an electricpaint remover device which is designed and constructed in such a mannerthat the many deficiencies of construction and operation which exist inprior devices of this type, Some of which have above been referred. to,are overcome, and which is also constructed so that the heating elementthereof will generate sucient intense heat to efficiently disintegratethe paint lm on a painted surface so that said paint lm may be rapidlystripped or scraped olf such surface.

A further object is to provide an electric paint remover in which theheating means thereof is so arranged and constructed that it Will beadequately protected and shielded against oxidation or deterioration andagainst mechanical injury.

A further object is to provide an electric paint remover constructionprovided with a heating means which may be brought into close relationto a painted surface without danger of re or electrical hazard andwithout injury to the heating means and also without said means becominggummed up or mechanically or electrically damaged by the heated plasticpaint.

A further object is to provide an electric paint remover constructionwhich has an aluminum reflecting shield so arranged and positioned withrespect to the heating means, and protected, that it will not lose itsreflectivity or be aiected by the heat generated by the heating means.

A further object is to pro-vide in an electric `paint remover, analuminum reflector for the heat rays produced by the heating meansthereof, which reflector is provided with both an upper and lower shinysurface, the lower shiny surface being adapted to turn back reectivelymost of the heat rays from the heating means reaching it and to directsaid rays downwardly toward the heating means, and the upper shinysurface functioning to block olf the small portion of said heat rayswhich will not be reflected by the lower shiny surface and whichordinarily Ywill be conducted upwardly through the metal of said shieldand cause the operating handle of the paint remover to heat up.

A further object is to provide a heating means for an electric paintremover which will provide a higher heating temperature than has beenproduced by heating elements heretofore used in electric paint removers,and which Will also have a longer life of use at high temperatures thanhas been possible with heating elements previously used.

A further object is to provide an improved construction of insulatingblock for supporting the resistance wires of the heating element.

A further object is to provide a novel assembly of an insulating blockin which the heating means is embedded and a metal sub-shield, so thatsaid insulating block and said sub-Shield comprise an ecient heatradiating unit with low conduction losses.

A further object is to provide an assembly of an insulating block havingthe resistance wire of the heating means embedded therein, with ametallic sub-shield, and so that the insulating block will be held bysaid sub-shield at an effective predetermined distance above a paintedsurface to be heated by the paint remover device.

A further object is to provide an electric paint remover constructionhaving a stainless steel sub-shield support for an insulating block inwhich the wire coils of a heating means are embedded, and which shieldis so mounted with respect to said block that any tendency of the blockto warp at its ends due to the heat conditions to which it is subjectedwill be eliminated.

A further object is to provide an electric paint remover device having astainless steelV shield for the insulating block in which the heatingcoils are imbedded, and which shield is so formed that it will provide abarrier along the edges of the block which will prevent outward chillingof the paint lm being removed, and also will func- -tion to retainwithin its walls the heat produced by said heating coils.

A further object is to provide in an electric paint remover device astainless steel shield support for the insulating block in which theheating coils of the device are embedded, and which shield together withsaid block forms as a whole a practical composite unit which may bereadily and quickly replaced as a unit in the burner construction.

A further object is to provide in an electric paint remover, asub-shield construction for supporting an insulating block in which theheating coils of the paint remover are positioned, and which shield issecured to said block in such manner that the conducted heat to theshield from the block is reduced to a minimum.

A further object is to provide an electric paint remover constructionwhich is adapted to be positioned in an upside down position on anysurface, during warmup periods, and so that it will be supported on onecorner of the reflecting shield and the handle thereof, and withoutdanger of the burner damaging the surface upon which it is sopositioned.

With the above and other objects in view, the

invention consists in the construction, arrange ment and combination ofthe various parts of the paint remover device, where the objectscontemplated are attained, as hereinafter more fully set forth, pointedout in the claims and illustrated in the accompanying drawings, in whichFigure 1 is a side elevational viewof the electrical paint removerembodying the features of my invention;

1 Figure 2 is an end elevational view of the paint remover and whereinparts of the interior construction thereof are indicated by spacedlines;

AFigure 3 is a top plan view with parts thereof shown broken away tomore clearly indicate the construction;

Figure 4 is a bottom plan view showing the insulating block in which theheating elements of the burner are embedded;

Figure 5 is an elevational side sectional view of the burnerconstruction.

lReferring particularly to the drawings, the electric paint remover ofmy invention includes in its construction a rectangular shapedinsulating block member A; the heating wire coils indicated generally atB; a sub-shield C a reflector shield D; a terminal cover E; the handlemember F; handle brackets G; and electrical conductor cord I-I extendingthrough said handle; theterminal bushings I; and the terminal tubecovers J which are adapted to enclose lthe ends of the wires of theheating coils.

The rectangular shaped insulating block may be made of porcelain or anyother suitable nonconducting heat resisting material and is providedwith a plurality of shallow grooves or channels l in the lower facethereof which extend length- Wise of said block (see Fig. 4). Mounted insaid grooves or channels is the coiled current conducting resistancewire B which forms the heating means of the paint remover. Theresistance Wire used for the heating means is of the type known asKanthal wire. This particular type of wire has'been found to possesscharacteristics which are not found in other types of electricalresistance wire which have heretofore been used in electric paintremover constructions and is adapted to operate at a higher temperaturethan other types of Wire used for electrical heating means. Also, aheating means employing Kanthal wire requires less wire per unit of heatthan most other resistance wires and, therefore, provides more heat in agiven area than is possible when other types of wire, such for instanceas Ntchrome wire are used. This type of resistance wire also has alonger life in use at high temperatures than is possessed by otherwires. The resistance wire coils B of the heating means are positionedin the grooves or channels l, of the insulating block A and are retainedtherein and insulated so as toprevent accidental contact therewith bythe operator of the paint remover device, by means of a cement indicatedat 3 (see Fig. 5). I have found that Sauereisen Cement No. 78 ispreferable for use in securing the resistance wire coils in the groovesof the porcelain block as other types of cement have proven.

to be unsatisfactory because they either :break down to a powder underthe severe heat conditions produced by the heating coils, or they arenot sufficiently adhesive in the presence of the heat produced toproperly retain the wire coils in place in said grooves, or they arepossessed of such a complete insulating characteristic that they willobstruct a` proper transfer of heat from the heating coils. SauereisenCement has the advantage over other types of cement in the fact that itis not only high in heat conductivity but it is also low in electricalconductivity, and even though the heating coils are embedded and coveredwith the same, radiation of heat from the block will not be greatlyimpaired. This type of cement, when it has set, also provides aporcelain-like surface over the face of the grooves and forms aprotection against the coils coming in contact with the user of thedevice.

Secured to the porcelain block A, and positicned in spaced relationthereto, by means of the screw bolts 4 and the nuts 5, is the sub-shieldC. The subushield is preferably made of stainless steel and is formed sothat it is provided with a top portion which completely covers the topsurface of the block A, and with the side Iwalls and 1 which extenddownwardly and enclose the side walls 8 and 9 of said block. The screwbolts ri and the nuts 5 secure the subshield to the block at fourseparated points along the center line of the channel formed by theshape of the sub-shield as clearly indicated in Figures 2 and 4. Thesefour small area points of contact are the only points of contact betweenthe block and the sub-shield, and thus the paths for conducting heatfrom the block to the sub-shield are reduced to a minimum.

The sub-shield C, together with the porcelain block A, with theresistance wire B embedded therein, comprise the heating unit of thepaint remover construction, which heating unit is of light weight andcan be readily and easily removed from the paint remover constructionand replaced by another similar heating unit if de-` sired.

The sub-shield C performs several important functions in the paintremover device of the invention. It provides a rigid longitudinalsupport for the porcelain insulating block A, and prevents said blockfrom warping at its ends from the heat transmitted to it by the heatingcoils. The sides Ei and l' of the sub-shield hold the insulating blockat a required distance above the painted surface to be heated by theheating coils, and the side member E provides a cleaning edge forcleaning paint from the scraper blade which is used in conjunction withthe paint remover device. The subeshield also forms a partial block toupward flowing radiant heat coming from the heating coils and a completebarrier to convected heat. It also provides a barrier along the edges ofthe porcelain block to outward chilling of the paint surface beingtreated by the paint remover device and also functions to retain theheat produced by 'the heating coils Within its walls. The method ofmounting the porcelain insulating block along the center line of thechannel formed by the shape of the sub-shield also gives to the block acertain amount of resiliency so that it is capable of absorbing shockswhich ordinarily would cause a more rigidly mounted block to break orcrack. Lastly, the sub-shield serves as a smoke shield and protects thereiiective surface of the aluminum shield D, which is to be furtherdescribed, from smoke and paint debris which would ordi'- narily tend todestroy the reectivity of said aluminum shield if the sub-shield was notused.

Positioned above the sub-shield C is the reflector shield D, which ispreferably made of aluminum. The reflector shield is adapted to stopIthe upward flowing radiant rays of heat coming from the heating coils B,and to reflect the same downwardly towards the heating means. Thereflector aware@ shield is made so that it is provided with a shinyupper surface. 32 and` a lower shiny surface 33. The lower shiny surface33 functions to reflect back most of the heat rays from the heatingcoils which reach it, and the small portion of said heat rays which arenot reflected back but which are conducted upwardly through the metal ofthe shield. are stopped at the upper shiny surface 32, said surfacehaving a low emissivity factor and thus will not re-radiate the heatrays that may reach it.

The aluminum reflector shield D is mounted above and in spaced relationto the sub-shield C, by means of three screw bolts Iii, II and I2', andthespacing bushings I9', II and I2', and is formed with the curveddownwardly extending sides I3 and I, which overlap the sides 6 and 1 ofthe sub-shield C'. It will be noted that the curved side I3 of thereflector shield does. not completely overhang the sub-shield along oneside of the paint remover. The curved side I3 is purposelyA formed inthis. manner and so that it is in line with the side G of the sub-shieldand does not overhang the same, and so that the paint remover device maybe moved directly into corners when it is being used. As is well known,there are times during the removing of paint from a painted surlace'thatit is necessary to get into corners or up to an upright, such asunderneath a cornice, or on a licor close to the mop board, and thearrangement of the curved side I3 of the reiiector shield with respectto the side 6 ofthe sub-shield, permits the burner device to be operatedso that it can be readily moved into such places.

Extending through the aluminum shield D, and alsothrough the sub-shieldC are the openings I and IS through which the free ends il and I8 of theKanthal wire of the resistance coils of the heating means extend.Positioned in said openings I5 and IS are the porcelain insulating tubesJ which surround the ends I and I8 of the resistance wire and extendupwardly within the terminal cover E. The ends il' and I8 of theresistance wire are adapted to be secured to the wire ends I9 and 2d or"the electrical conductor cord H which extendsr through the wooden handleF of the paint remover device. It will be noted that it is intended thatthe ends I9 and 20 of the wire of the electrical conductor cord Hbinding the connection by means of the solderless conically threadedthimble-shaped insulating bushings l, which function not only as bindersfor the connection but also as electrical insulators to enclose saidconnection.

The terminal connection which is provided between the ends I'I and I8 ofthe heating element wires and the wire ends I9 and 20 of the electricalconducting coil H, is one of the novel :features of the construction ofthe paint remover device of the present invention. In the usual electricpaint remover constructions the ends of the resistance wires of theheating means are brought to terminal screws on a plate mounted in thehandle. attachment of the device. This is common practice in connectionwith the construction of medium temperature electrical burner devices,but such an arrangement would cause constant trouble in a burner deviceusing high temperatures in trying to maintainv good contact, unless thecontacts were actually welded 8 tothe plate. In the present constructionthe ends of the resistance wires are brought out to a relatively coolarea and then are bent back on themselves to reduce. the resistance ofthe wire at this z point lbelow the self heatingl point and so that theyare cool exceptA for the heat conducted through the metal of. the wire,and at this point they are connected directly with the ends of the wiresof the electrical conductor cord H.

Secured to the base portion 2l of the Wooden handle E by means of thescrew bolts 22 and 23 and nuts 24 and 25, are the vertically extendinglegs 26 and 21 of the handle brackets G. The horizontally extending legs26' and 21,' of said brackets extend lengthwise over the top of thealuminum shield D, and are secured at their ends 28 and 29 to the shieldby means of the screw bolts III and II. so that the legs thereof areheld to a. minimum in cross-section and so that they will not providetoo-large a path for the passage of conducted heat from the heatingcoils. It will also be observed thatA the handle F of thepaint removerconstruction is not connected directly to the aluminum shield D, but isonly connected thereto through said brackets G, This arrangement alsoprovides for a cool operating handle for the paint remover construction.

Secured to the base portion 2l of the handle member F, by means of thescrew bolts 22 and 23, and the nuts 2d and 25, is the rectangularshaped, three-sided terminal. cover E which is adapted to enclose theterminal connection of the ends of the wires from the heater coils andthe ends of the Wires of the electrical conductor cord H. The terminalcover E is provided with the slotted openings 3d and 35 in the sidewalls 36 and 35i thereof, which slotted openings are adapted to receivethe. screw bolts 22 and 23. By reason of said slotted openings 34 and35' said terminal cover may be removably secured to the base portion 2Iof the handle F, and thus may be readily taken oi of the paint removerdevice so that the terminal connection of the wires Il, I8, I9 and 2i)may be inspected or repaired when necessary by merely loosening up onthe nuts 24 and 25.

Mounted within the terminal cover E and positioned over the terminalconnection made between the heating element wires il and I8 and the wireends I9 and 2li of. the conductor cord H, are the ceramic solderlessthimble-shaped bushings I. These terminal bushings provide an efiectivemeans for joining dissimilar metals such as Kanthal wire used for theheating coils and the copper wires yused in the electrical conductorcord, operating under severe heat conditions, and there will thus occurvno breakdown of the connection of the wires due to oxidation ofthecopper wire and also good contact between the two types of wire willbe definitely maintained.

It will be seen from the above descriptionof my improved electric paintremover that it incorporates therein many novel features of constructionwhich are not found in prior paint removers of this type or whichovercome the defects in construction and operation which have existed insuch paint removers. It will also be obvious that my invention issusceptible to some change and modification without departing from theprinciples and spirit thereof, and for this reason I do not want to beunderstood as limiting myself to the precise arrangement and formationof the several parts herein shown in carrying out my invention, exceptas hereinafter claimed.

I claim:

The handle brackets are made 1. An electric paint remover comprising anelectric heat radiating means imbedded in an insulating support, ametallic shield secured to and in spaced relation to said heat radiatingmeans and forming a heat confining housing enclosing said heat radiatingmeans, a metallic shield of high heat rellectivity secured to said irstmenticned shield and mounted above and in spaced relation theretoforming an air space therebetween, an operating handle mounted on said'z heat reilecting shield through connectors of reduced cross section,and electrical conductor means extending through said handle andconnected to said heating means for supplying electric current thereto.

2. An electric paint remover comprising an electric heat radiating meansimbedded in an insulating body, a metallic shield secured to and inspaced relation to said heat radiating means through connectors ofsubstantially reduced cross 1i section and forming a heat conininghousing enclosing said heat radiating means, a metallic heat reectingshield secured to said lirst mentioned shield through connectors ofreduced cross section and mounted above and in spaced relation thereto,and having reecting surfaces on the under and upper faces thereof, saidunder reilecting surface being adapted to reflect downwardly heat raysradiating upwardly from said heating means and from said first mentionedshield and i-J said upper reflecting surface being adapted to block theupward ow of heat rays conducted through the metal of said shield, anoperating handle mounted on said heat reflecting shield, and electricalconductor means extending through said handle and connected to saidheating means for supplying electrical current thereto.

3. An electric paint remover comprising an electric heating meanspositioned in the lower face of a rectangular shaped block ofnon-conducting and heat resisting material, a metallic heat blockingshield positioned over said block and secured in spaced relation to thesame through connectors of reduced cross section and so as to provide anair space between said block and shield, said shield being formed withdownwardly extending side portions which enclose the sides of said blockand which support said block a s heating element for supplyingelectrical current thereto.

4. An electric paint remover comprising an electric heating meanspositioned in a rectangular shaped block member made of a non-conductingi. and heat resisting material, a metallic shield mounted over andsecured to said block member and in spaced relation thereto and havingdownwardly extending side walls and open ends, said side walls enclosingthe sides of said block member and also being adapted to support saidblock member a predetermined distance above the painted surface to beheated by the heating means of the paint remover, said shield and blockmember forming a complete assembly adapted to be removably positioned asa unit in the paint remover, an aluminum shield having heat refleetingsurfaces secured to and over said rst mentioned metallic shield and inspaced relation thereto, an operating handle secured to said aluminumshield for manipulating the paint remover, and an electrical conductormeans extending through said handle and connected to said heating meansfor supplying electrical current thereto.

LOUIS M. CARPENTER.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number

